Levofloxacin pharmacokinetics and serum bactericidal activities against five enterobacterial species.

ABSTRACT

After oral administration of 500 mg of levofloxacin to 12 volunteers, we investigated the pharmacokinetics and serum bactericidal activities (SBAs) against five strains of members of the family Enterobacteriaceae. Pharmacokinetic data were as follows maximum concentration in serum, 6.36 +/- 0.57 mg/liter; area under the concentration-time curve, 43.6 +/- 6.23 mg. h/liter; elimination half-life 4.23 +/- 0.87 h. SBAs were present for 24 h against Escherichia coli and Citrobacter freundii. The SBAs at 1, 12, and 24 h after administration against E. coli were 1108, 129, and 17, respectively, and those against Citrobacter freundii were 174, 125, and 17, respectively. The SBAs were present for 12 h against the other three organisms tested. The SBAs against Serratia marcescens were 128 and 19 at 1 and 12 h, respectively; the SBAs against Klebsiella pneumoniae were 125 and 17 at 1 and 12 h, respectively; and the SBAs against Enterobacter cloacae were 124 and 110 at 1 and 12 h, respectively.